Display screen or portion thereof with a graphical user interface



FIG. 1 is a perspective view of a display screen or portion thereof with a graphical user interface comprising the present invention.

FIG. 2 is a perspective view of another embodiment of a display screen or portion thereof with a graphical user interface comprising the present invention.

FIG. 3 is a perspective view of another embodiment of a display screen or portion thereof with a graphical user interface comprising the present invention; and,

FIG. 4 is a perspective view of another embodiment of a display screen or portion thereof with a graphical user interface comprising the present invention.

The broken lines illustrate a display screen or portion thereof and form no part of the claimed design. The broken lines seen in FIG. 4 illustrate portions of the graphical user interface and form no part of the claimed design. 

CLAIM We claim the ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 